gdb does not stop on breakpoint in emacs, but does stop in commandline mode

gdb does not stop on breakpoint in emacs, but does stop in commandline mode

[John Murray]

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I set a breakpoint in a shared library in gdb on emacs run the program and
the breakpoint is ignored.

If I follow the same procedures in gdb from the command line, gdb stops at
the breakpoint.


emacs version:  25.3.1
gdb version:  7.2-75.e16
gdb-mi.el loaded

More detail:

I start gdb in emacs using the command:

gdb -i=mi /path to executable/executable

> break main
> run
> info func .*ProcessCommand.*
...
[address of desired function]

> break *[address of the desired funciton]
> continue

Using this sequence inside emacs, gdb ignores the breakpoint.
Using this sequence using gdb from the command line, the code stops at the
breakpoint.

I note that the function is in a shared library.

Any suggestions would be appreciated.

Thank you!

john
-- 

*John W. Murray*
John@gardenway.org <Michael@HepworthMurray.com>
801-628-0543

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Re: gdb does not stop on breakpoint in emacs, but does stop in commandline mode

[Eli Zaretskii]

> From: John Murray <john@gardenway.org>
> Date: Thu, 28 Dec 2017 07:58:45 -0700
> 
> I set a breakpoint in a shared library in gdb on emacs run the program and the breakpoint is ignored.
> 
> If I follow the same procedures in gdb from the command line, gdb stops at the breakpoint.
> 
> emacs version:  25.3.1
> gdb version:  7.2-75.e16
> gdb-mi.el loaded
> 
> More detail:
> 
> I start gdb in emacs using the command:
> 
> gdb -i=mi /path to executable/executable
> 
> > break main
> > run
> > info func .*ProcessCommand.*
> ...
> [address of desired function]
> 
> > break *[address of the desired funciton]
> > continue
> 
> Using this sequence inside emacs, gdb ignores the breakpoint.
> Using this sequence using gdb from the command line, the code stops at the breakpoint.
> 
> I note that the function is in a shared library.

I couldn't reproduce this with GDB 7.8.1 and the current emacs-26
branch of the Emacs Git repository: your recipe works for me both
inside and outside Emacs.  Not sure that the newer versions are the
reason, though.  However, GDB 7.2 is quite old, so maybe try to
upgrade that first.

(For the record, I tried debugging Emacs, and set a breakpoint at
inflateEnd, which is a zlib function.  Then I invoked
zlib-decompress-region to trigger the breakpoint.)